Jean-Paul Rodrigue (2013), New York:
Routledge, 416 pages.
The Cold Chain and its Logistics
Authors: Dr. Jean-Paul Rodrigue and Dr. Theo Notteboom
While Globalization has made the relative distance between regions
of the world much smaller, the physical separation of these same regions
is still a very important reality. The greater the physical separation,
the more likely freight can be damaged in one of the complex transport
operations involved. Some goods can be damaged by shocks while others
can be damaged by undue temperature variations. For a range of goods
labeled as perishables, particularly food, their quality degrades
with time since they maintain chemical reactions which rate can be
mostly mitigated with lower temperatures. It takes time and coordination
to efficiently move a shipment and every delay can have negative consequences,
notably if this cargo is perishable. To ensure that cargo does
not become damaged or compromised throughout this process, businesses
in the pharmaceutical, medical and food industries are increasingly
relying on the cold chain technology.
The cold chain involves the transportation of temperature
sensitive products along a supply chain through thermal and refrigerated
packaging methods and the
logistical planning to protect the
integrity of these shipments.
Specialization has led many companies to not only rely on major shipping
service providers such as the United Parcel Service (UPS) and Fedex,
but also more focused industry specialists that have developed a niche
logistical expertise around the shipping of temperature sensitive products.
The potential to understand local rules, customs and environmental conditions
as well as an estimation of the length and time of a distribution route
make them an important factor in global trade. As a result, the logistics
industry is experiencing a growing level of specialization and segmentation
of cold chain shipping in several potential niche markets within global
commodity chains. Whole new segments of the distribution industry have
been very active in taking advantage of the dual development of the
spatial extension of supply chains supported by globalization and the
significant variety of goods in circulation. From an economic development
perspective, the cold chain enables many developing countries to take
part in the global perishable products market. From a geographical perspective,
the cold chain has the following impacts:
2. Emergence of Cold Chain Logistics
While global commodity chains are fairly modern expansions in the
transportation industry, the refrigerated movement of temperature sensitive
goods is a practice that dates back to 1797 when British fishermen used
natural ice to preserve their fish stock piles while at sea. This process was also
seen in the late 1800s for the movement of food from rural areas to
urban consumption markets, namely dairy products. Cold storage was also
a key component of food trade between colonial powers and their colonies.
For example, in the late 1870s and early 1880s, France was starting
to receive large shipments of frozen meat and mutton carcasses from
South America, while Great Britain imported frozen beef from Australia
and pork and other meat from New Zealand. This process was incited
by a shortage of meat production in Europe and substantial surpluses
in developing countries. By 1910, 600,000 tons of frozen
meat was being brought into Great Britain alone. The first reefer
ship for the banana trade was introduced in 1903 by the United Food
Company. This enabled the banana to move from an exotic fruit that
had a small market because it arrived in markets too ripe, to one of
the world's most consumed fruit. Its impacts on the reefer industry
were those monumental.
The temperature controlled movement of pharmaceuticals and medical
supplies is a much more modern transit option than the shipping of refrigerated
or frozen food. Since the 1950s, logistical third party companies began
to emerge and institute new methods for successfully transporting these
global commodities. Before their emergence, cold chain processes were
mostly managed in house by the manufacturer. In the United States, Food
and Drug Administration restrictions and accountability measures over
the stability of the cold chain incited many of these companies to rely
on specialty couriers rather than completely overhauling their supply
chain facilities. A specialized industry was thus born. The value of
the cold chain in the preservation of expensive vaccines and medical
supplies was only beginning to be recognized when these logistical providers
started to appear. As awareness began to grow, so did the need for efficient
management of the cold chain.
The reliance on the cold chain continues to gain importance. Within
the pharmaceutical industry for instance, the testing, production and
movement of drugs relies heavily on controlled and uncompromised transfer
of shipments. A large portion of the pharmaceutical products that move
along the cold chain are in the experiment or developmental phase. Clinical
research and trials is a major part of the industry that costs millions
of dollars, but one that also experiences a failure rate of around 80%.
According to the Healthcare Distribution Management Association, of
the close to 200 billion dollars in pharmaceutical distribution, about
10% are drugs that are temperature sensitive. This makes the cold chain
responsible for transporting a near 20 billion dollar investment. If
these shipments should experience any unanticipated exposure to variant
temperature levels, they run the risk of becoming ineffective or even
harmful to patients.
Temperature control in the shipment of foodstuffs is a component
of the industry that has continued to rise in necessity with international
trade. As a growing number of countries focus their export economy around
food and produce production, the need to keep these products fresh for
extended periods of time has gained in importance. Increasing income
levels create a change in diet with amongst others a growing
appetite for fresh fruit and higher value foodstuffs such as meat
and fish. Persons with higher socioeconomic status and with more
economic means are more likely to consume vegetables and fruit,
particularly fresh, not only in higher quantities but also in
greater variety. Consumers with increasing purchase power have
become preoccupied with healthy eating, therefore producers and
retailers have responded with an array of exotic fresh fruits
originating from around the world.
Any major grocery store around the world is likely to carry
tangerines from South Africa, apples from New Zealand, bananas from
Costa Rica and asparagus from Mexico. Thus, a cold chain industry has
emerged to service these commodity chains.
Alone, the United States imports about 30% of its fruits and vegetables
and 20% of its food exports can be considered perishables. The uncompromised
quality and safety of this food is often taken for granted, despite
being the main reason behind the ability to sell the food. The cold
chain serves the function of keeping food fresh for extended periods
and eliminating doubts over the quality of the food products. In all
the supply chains it is concerned with, cold chain logistics favor
higher levels of integration since maintaining temperature integrity
requires a higher level of control of all the processes involved. It
may even incite third party logistics providers to acquire elements
of the supply chain where time and other performance factors are the
most important, even farming. This may involve the acquisition of
produce farms (e.g. oranges) to insure supply reliability.
3. Providing Temperature Controlled Environments
The success of industries that rely on the cold chain comes down
to knowing how to ship a product with temperature control adapted to
the shipping circumstances. Different products require different temperature
level maintenance to ensure their integrity throughout the travel process.
For instance, the most common
temperature standards are "banana"
(13 °C), "chill" (2 °C), "frozen" (-18 °C)
and "deep frozen" (-29 °C). Staying within this temperature
is vital to the integrity of a shipment along the supply chain and
for perishables it enables to insure and
optimal shelf life. Any
divergence can result in irrevocable and expensive damage; a product
can simply lose any market or useful value.
Being able to ensure that
a shipment will remain within a temperature range for an extended period
of time comes down largely to the type of container that is used and
the refrigeration method. Factors such as duration of transit, the size
of the shipment and the ambient or outside temperatures experienced
are important in deciding what type of packaging is required. They can
range from small insulated boxes that require dry ice or gel packs,
rolling containers, to a 53 footer reefer which has its own powered
refrigeration unit. The major cold chain technologies involve:
- Global. Specialization of agricultural functions permitting
the transport of temperature sensitive food products to distant
markets. Enables the distribution of vaccines and other pharmaceutical
or biological products from single large facilities.
- Regional. Can support the specialization of
and economies of scale in distribution. This could involve specialized laboratories
exchanging temperature sensitive components or large
cold storage facilities
servicing regional grocery markets.
- Local. Timely distribution to the final consumer of
grocery stores and restaurants.
Refrigerated containers (called "reefers")
represent a specific category that
account for a growing share of the
refrigerated cargo being transported
around the world. While in 1980 33% of the refrigerated transport capacity
in maritime shipping was containerized, this share rapidly climbed to
47% in 1990, 68% in 2000 and 90% in 2010. About 1.69 million TEUs of
reefers were being used by 2009. While a regular 40 foot container
costs around $5,000, a reefer is in the range of $30,000. The cost
difference is attributed to insulation and the refrigeration unit that
keeps the temperature constant. All reefers are painted white to increase
the albedo (share of the incident light being reflected; high albedo
implies less solar energy absorbed by the surface) with the dominant
size being 40 high-cube footers (45R1 being the size and type code).
For instance a low albedo container can have its internal temperature
increase to 50 °C when the external temperature reaches 25 °C on a sunny
day while a high albedo container see its internal temperature increase
to only 38 °C under the same conditions.
The refrigeration unit of a reefer requires an electric power source
during transportation and at a container yard. Regular
containerships have 10 to 20% of their slots adapted to carry
reefers, with some ships having up to 25% of their slots being
dedicated when servicing routes with a higher intensity of
refrigerated cargo. It is important to underline
that the refrigeration units are designed to maintain the temperature
within a prefixed range, not to cool it down. This implies that the
shipment must be brought to the required temperature before being loaded
into a reefer, which requires specialized warehousing and loading /
unloading facilities. A new generation of reefers is coming online,
which are equipped with an array of sensors monitoring effectively the
temperature and shutting the cooling plant when unnecessary. This enables
to improve the reliability of temperature control and well as extend
the autonomy of the reefer.
The growth of the intermodal transportation of reefers has increasingly
required transport terminals, namely ports, to dedicate a part of their
to reefers. This accounts between 1% to 5% of the total terminal
capacity, but can be higher for transshipment hubs. The stacking requirements
simply involve having an adjacent power outlet, but the task is more
labor intensive as each container must be plugged and unplugged manually
and the temperature to be monitored regularly as it is the responsibility
of the terminal operator to insure that the reefers keep their temperature
within preset ranges. This may also forbid the usage of an overhead
gantry crane implying that the reefer stacking area can be serviced
by different equipment. Even if reefers involve higher terminal costs,
they are very profitable due to the high value commodities they transport.
4. The Setting and Organization of Cold Chains
Moving a shipment across the supply chain without suffering any setbacks
or temperature anomalies requires the establishment of a comprehensive
logistical process the maintain the shipment integrity.
This process concerns several phases ranging from the preparation of
the shipments to final verification of the integrity of the shipment
at the delivery point:
- Dry ice. Solid carbon dioxide, is about -80°C and is
capable of keeping a shipment frozen for an extended period of time.
It is particularly used for the shipping of pharmaceuticals, dangerous
goods and foodstuffs. Dry ice does not melt, instead it sublimates
when it comes in contact with air.
- Gel packs. Large shares of pharmaceutical and medicinal
shipments are classified as chilled products, which means they must
be stored in a temperature range between 2 and 8°C. The common method
to provide this temperature is to use gel packs, or packages that
contain phase changing substances that can go from solid to liquid
and vice versa to control an environment. Depending on the shipping
requirements, these packs can either start off in a frozen or refrigerated
state. Along the transit process they melt to liquids, while at
the same time capturing escaping energy and maintaining an internal
- Eutectic plates. The principle is similar to gel packs.
Instead, plates are filled with a liquid and can be reused many
- Liquid nitrogen. An especially cold substance, of about
-196°C, used to keep packages frozen over a long period of time.
Mainly used to transport biological cargo such as tissues and organs.
It is considered as an hazardous substance for the purpose of transportation.
- Quilts. Insulated pieces that are placed over or around
freight to act as buffer in temperature variations and to maintain
the temperature relatively constant. Thus, frozen freight will remain
frozen for a longer time period, often long enough not to justify
the usage of more expensive refrigeration devices. Quilts can also
be used to keep temperature sensitive freight at room temperature
while outside conditions can substantially vary (e.g. during the
summer or the winter).
- Reefers. Generic name for a temperature controlled container,
which can be a van, small truck, a semi or a standard ISO container.
These containers, which are insulated, are specially designed to
allow temperature controlled air circulation maintained by an attached
and independent refrigeration plant. The term increasingly apply
to refrigerated forty foot ISO containers. Technological
advances are making them much less
prone to defects.
Therefore, the setting and operation of cold chains is dependent
on the concerned supply chains since each cargo unit to be carried has
different requirements in terms of demand, load integrity and transport
integrity. Because of the additional tasks involved as well as the
energy required for the refrigeration unit transportation costs for cold
chain products is much higher than regular goods. For instance, maritime
There is a variety of methods for the transport of food products
with the banana accounting for the world's most significant
commodity transported in the food cold chain with
20% of all
seaborne reefers trade.
Land, sea and air modes all have different structures for keeping food
fresh throughout the transport chain. Innovations in packaging, fruit
and vegetable coatings, bioengineering (controlled ripening), and other
techniques reducing the deterioration of food products have helped shippers
extend the reach of perishable products. For food products such as fruits
and vegetables, time has a direct impact on their shelf life and therefore
on the potential revenue a consignment may generate. Concomitantly,
new transport technologies have permitted the shipment of perishable
products over longer distances. For instance, improved roads and intermodal
connections along the African coast reduced food transport time to European markets from 10 days to 4 days.
Certain domestic or transnational supply chains may only require
one transportation mode, but many times ground shipments are one link
in a combination of transport modes. This makes intermodal transfer
critical for the cold chain. Intermodal shipments typically use either
20 or 40 footers refrigerated containers that are capable of holding
up to 26 tons of food. The container makes loading and unloading periods
shorter and less susceptible to experiencing damage. The environments
in these containers are currently controlled electronically by either
plugging into a generator or power source on the ship or truck, but
early food shipments would cycle air from stores of wet or dry ice to
keep the food refrigerated. The efficiency of cold chain logistics
permitted the consolidation
of cold storage facilities.
Moving away from ice refrigeration has allowed for much greater distances
to be traveled and has greatly increased the size of the global food
market, enabling many developing countries to capture
new opportunities. Another efficient
mode for transporting foodstuffs is air travel. While this is a preferred
form of travel for highly perishable and valuable goods due to its ability
to move much faster over longer distances, it does lack the environment
control and transfer ease of the ground and sea transports. Also, during
the flight the cargo is stored in a 15°C – 20°C environment, but close
to 80% of the time the package is exposed to exterior weather while
waiting to be loaded onto the plane or being moved to and from the airfield.
This is troubling considering the value of the food and the importance
placed behind quality and freshness. In order for this form of food
transport to experience growth among market users, more uncompromising
strategies and regulations will have to be embraced and enacted.
Food transportation is an industry that has fully adapted to the
cold chain and can, despite the problems with air transport, be considered
the most resilient, particularly since a large majority of food products
have a better tolerance to temporary variations of transport temperatures.
As a result, small errors can be compounded without the concern of irreversible
damage. For instance, for the transportation of produces, for every
hour of delay in the pre-cooling of shipments, an equivalent one day
loss of shelf life must be accounted. The usage of refrigerated containers
has particularly helped, since they account for more than 50% of all
the refrigerated cargo transported in the world. Source
loading can be an important factor extending the shelf life
of a cold chain product since it is loaded in a reefer directly at
the place of production without additional handling. For instance,
source loading into a reefer can expand the shelf life of
meat by about 25 days (from 30-35 days to 55-60 days) from
conventional methods and thus considerably expand the market
potential of the product.
The efficiency and
reliability of temperature controlled transportation has reached a point
which allows the food industry to take advantage of global seasonable
variations, meaning that during the winter the southern hemisphere can
export perishable goods to the northern hemisphere while an opposite
trade, generally of smaller scale, takes place during the summer. Countries
such as Chile have substantially benefited from this and have developed
an active agricultural and food transformation industry mainly servicing
the North American market during the winter, but also with several niche
markets such as wine. A similar issue concerns some African countries
such as Kenya that have developed a fresh produce and
flower industries catering
the European market. The fast food industry is also an active user
of cold chain logistics as every outlet can be considered as a factory, with dozens
of workers with schedules and shifts, inventory management and the supply
chain of components (many of which are temperature sensitive), and
which are assembly lines producing quality-controlled and
- Shipment preparation. When a temperature sensitive product
is being moved, it is vital to first assess its characteristics.
A key issue concerns the temperature conditioning of the shipment,
which should be already at the desired temperature. Cold chain devices
are commonly designed to keep a temperature constant, but not to
bring a shipment to this temperature, so they would be unable to
perform adequately if a shipment is not prepared and
conditioned. Other concerns
include the destination of the shipment and the weather conditions
for those regions, such as if the shipment will be exposed to extreme
cold or heat along the transport route.
- Modal choice. Several key factors play into how the shipment
will be moved. Distance between the origin and the final destination
(which often includes a set of intermediary locations), the size
and weight of the shipment, the required exterior temperature environment
and any time restrictions of the product all effect the available
transportation options. Short distances can be handled with a van
or truck, while a longer trip may require an airplane or a container
ship. If container transportation is required, than reefers are
usually stacked in a specific part of the terminal having power
to supply the refrigerated units.
- Custom procedures. If the freight crosses boundaries,
custom procedures can become very important, since cold chain products
tend to be time sensitive and more subject to inspection than regular
freight (e.g. produce, pharmaceuticals and biological samples). The difficulty
of this task differs depending on the nation (or economic bloc)
and the gateway since there are variations in procedures and delays.
- The "Last Mile". The last stage is the actual
delivery of the shipment to its destination, which in logistics
is often known as the “last mile”. Key considerations when arranging
a final delivery concern not only the destination, but the timing.
Trucks and vans, the primary modes of transportation for this stage,
must meet the specifications necessary to transfer the cold chain
shipment. Also important is the final transfer of the shipment into
the storage facilities as there is potential for a breach of integrity.
- Integrity and quality assurance. After the shipment has
been delivered, any temperature recording devices or known temperature
anomalies must be recorded and made known. This is the step of the
logistical process that creates trust and accountability, particularly
if liability for a damaged shipment is incurred. If problems or
anomalies that compromise a shipment do occur, an effort must be
made to identify the source and find corrective actions.